Improve cluster sidecar documentation (#573)

docs/reference/cluster_manifest.md

@@ -270,3 +270,36 @@ defined in the sidecar dictionary:
   a dictionary of environment variables. Use usual Kubernetes definition
   (https://kubernetes.io/docs/tasks/inject-data-application/environment-variable-expose-pod-information/)
   for environment variables. Optional.
+
+* **resources** see below. Optional.
+
+#### Sidecar container resources
+
+Those parameters define [CPU and memory requests and
+limits](https://kubernetes.io/docs/concepts/configuration/manage-compute-resources-container/)
+for the sidecar container. They are grouped under the `resources` key for each sidecar.
+There are two subgroups, `requests` and `limits`.
+
+##### Requests
+
+CPU and memory requests for the sidecar container.
+
+* **cpu**
+  CPU requests for the sidecar container. Optional, overrides the
+  `default_cpu_requests` operator configuration parameter. Optional.
+
+* **memory**
+  memory requests for the sidecar container. Optional, overrides the
+  `default_memory_request` operator configuration parameter. Optional.
+
+##### Limits
+
+CPU and memory limits for the sidecar container.
+
+* **cpu**
+  CPU limits for the sidecar container. Optional, overrides the
+  `default_cpu_limits` operator configuration parameter. Optional.
+
+* **memory**
+  memory limits for the sidecar container. Optional, overrides the
+  `default_memory_limits` operator configuration parameter. Optional.

docs/user.md

@@ -270,6 +270,13 @@ spec:
   sidecars:
     - name: "container-name"
       image: "company/image:tag"
+      resources:
+        limits:
+          cpu: 500m
+          memory: 500Mi
+        requests:
+          cpu: 100m
+          memory: 100Mi
       env:
         - name: "ENV_VAR_NAME"
           value: "any-k8s-env-things"

manifests/complete-postgres-manifest.yaml

@@ -71,3 +71,17 @@ spec:
   maintenanceWindows:
   - 01:00-06:00 #UTC
   - Sat:00:00-04:00
+  #sidecars:
+  #  - name: "telegraf-sidecar"
+  #    image: "telegraf:latest"
+  #    resources:
+  #      limits:
+  #        cpu: 500m
+  #        memory: 500Mi
+  #      requests:
+  #        cpu: 100m
+  #        memory: 100Mi
+  #    env:
+  #      - name: "USEFUL_VAR"
+  #        value: "perhaps-true"
+